Practice S3.1 The periodic table: Classification of elements with authentic IB Chemistry exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like atomic structure, chemical reactions, and organic chemistry. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
A research team investigates the chemical behavior of Period 3 oxides to understand their industrial and environmental applications. The team analyzes the following oxides: , , and .
Classify the type of bonding in each of the following oxides and relate it to their position in Period 3:
Describe the trend in acid–base character of the oxides across Period 3 from sodium to chlorine.
Predict whether reacts with both acids and bases, and justify your answer using acid–base theory.
Group 1 metals react vigorously with water.
Write a balanced chemical equation for the reaction of lithium with water.
Compare the reactivity of lithium and potassium with water.
Explain the trend in reactivity of Group 1 elements down the group using atomic structure.
Electron configurations reveal periodic patterns.
State the number of valence electrons in an atom of oxygen.
Deduce the electron configuration of phosphorus ().
Explain how the group number relates to the number of valence electrons.
The graph of first ionization energy across Period 3 shows small irregularities.
Define first ionization energy.
Explain the general trend in first ionization energy across Period 3.
Account for the lower ionization energy of aluminum compared to magnesium, despite the overall trend.
Explain why sulfur also has a slightly lower first ionization energy than phosphorus.
Group 17 elements show a trend in oxidizing ability.
Write a balanced ionic equation for the reaction between chlorine and potassium iodide.
Identify the halogen reduced and state its change in oxidation state.
Explain why chlorine displaces iodine from its salt.
Elements in Period 2 demonstrate periodic trends.
Describe the trend in first ionization energy across Period 2.
Explain this trend using atomic structure.
Account for the lower first ionization energy of boron compared to beryllium.
The electron affinity (EA) of an element reflects its ability to gain electrons and form negative ions. The values for some Period 3 elements are given below:
| Element | Electron Affinity / |
|---|---|
| Na | –53 |
| Mg | +8 |
| Al | –44 |
| Si | –134 |
| P | –72 |
| S | –200 |
| Cl | –349 |
Define the term electron affinity.
Explain why the first electron affinity of magnesium is positive, unlike other Period 3 elements.
Compare and explain the relative electron affinities of sulfur and chlorine based on atomic structure.
Use the data to describe and explain the general trend in electron affinity across Period 3, noting any anomalies.
The concept of oxidation state is essential for understanding redox reactions, industrial chemistry, and environmental oxidation processes.
Define the term oxidation state, and explain its relevance in redox chemistry.
Determine the oxidation number of sulfur in each of the following compounds: , ,
Explain, using electron transfer principles, why the oxidation number of any element in its standard (elemental) form is always zero.
In acid rain chemistry, both and are atmospheric pollutants. Compare their oxidation states and discuss how sulfur is transformed in the atmosphere.
Transition metal complexes absorb visible light and appear coloured.
State the type of electronic transition that causes colour in these complexes.
Explain how ligand interaction causes d-orbital splitting in transition metal complexes.
A complex ion appears blue. Use the colour wheel to determine what colour of light it absorbs.
Coloured complexes are important in analytical chemistry.
Explain why forms colourless solutions, while forms blue ones.
Describe one use of colorimetry in determining the concentration of a solution.
The ion appears blue. Suggest what change would occur if replaces as a ligand.